Human reproduction
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Mifepristone interrupts folliculogenesis in women but the mechanism is not clear. Previous studies have investigated the effect of this compound on gonadotrophin secretion and have provided conflicting results. To study further the effect of mifepristone on basal and gonadotrophin-releasing hormone (GnRH)-induced gonadotrophin secretion, 12 normally ovulating women were investigated during two consecutive menstrual cycles, comprising an untreated cycle (control) and a cycle treated with mifepristone. ⋯ We conclude that the disruption of folliculogenesis by mifepristone cannot be explained by a decrease in basal FSH concentrations during the critical period of follicle recruitment and selection. It is possible that mifepristone exerts its effect at the level of the ovary. It is also suggested that progesterone during the follicular phase of the cycle may participate in the control of the self-priming action of GnRH on the pituitary.